Google Base is an attempt to overcome Froogle failure (Renamed to Google product search now). Google base works with Google product search, but still they are different. The main reason of this is define in this undocumentment part of it

http://googleproducts.blogpico.com/

Can €™t find your items in Google Product Search. Why ?

Earlier their was only one Google portal to sell your products that was Froogle. Then, Google introducded Google base and changed the of Froogle to Google Product Search.

If you can €™t find out your items or some of your items in Google product search. They might be listed in Google base. There are few reason behind this and they are as follows:

product_type: Product type indicate the category of your product. This field is very important to include in your feed. Otherwise, Your products will be listed in Google base not Google Product Search.

price : Price is another field you should include in your feed.

location : Location is the last important field you should not forget to include in your feed. It indicate

 If your products are not listed on both, check for errors in your feed.

hope this Article define what I mean.